1. Field of the Invention
This invention relates to an image recording apparatus, wherein a photographic material is exposed to light, which has been modulated in accordance with an image signal, and an image represented by the image signal is thereby recorded on the photographic material.
2. Description of the Prior Art
Image recording apparatuses, wherein a photographic material is exposed to light, which has been modulated in accordance with an image signal, and an image represented by the image signal is thereby recorded (reproduced) on the photographic material, have heretofore been used in various fields.
For example, as disclosed in Japanese Patent Publication No. 61(1986)-5193, an X-ray image is recorded on an X-ray film having a small gamma value chosen according to the type of image processing to be carried out, the X-ray image is read out from the X-ray film and converted into an electric signal, and the electric signal (image signal) is processed and then used in an image recording apparatus for reproducing the X-ray image as a visible image on photographic film. In this manner, a visible image having good image quality with high contrast, high sharpness, high graininess, or the like, can be reproduced.
Also, when certain kinds of phosphors are exposed to radiation such as X-rays, .alpha.-rays, .beta.-rays, .gamma.-rays, cathode rays or ultraviolet rays, they store part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays, such as visible light, light is emitted by the phosphor in proportion to the amount of energy stored thereon during its exposure to the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
As disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318, 4,387,428, and Japanese Unexamined Patent Publication No. 56(1981)-11395, it has been proposed to use stimulable phosphors in radiation image recording and reproducing systems. Specifically, a radiation image of an object, such as a human body, is recorded on a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet, on which the radiation image has been stored, is then scanned with stimulating rays, such as a laser beam, which cause it to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation. The light emitted by the stimulable phosphor sheet, upon stimulation thereof, is photoelectrically detected and converted into an electric image signal. The image signal is then used in an image recording apparatus for reproducing the radiation image of the object as a visible image on photographic film.
Radiation image recording and reproducing systems which use stimulable phosphor sheets are advantageous over conventional radiography using silver halide photographic materials, in that images can be recorded even when the energy intensity of the radiation to which the stimulable phosphor sheet is exposed varies over a wide range. More specifically, since the amount of light which the stimulable phosphor sheet emits when being stimulated varies over a wide range and is proportional to the amount of energy stored thereon during its exposure to the radiation, it is possible to obtain an image having a desirable density regardless of the energy intensity of the radiation to which the stimulable phosphor sheet was exposed. In order for the desired image density to be obtained, an appropriate read-out gain is set when the emitted light is being detected and converted into an electric signal to be used in the reproduction of a visible image on a recording material, such as a photographic material, or on a display device, such as a CRT display device.
As described above, with image recording apparatuses utilized in various types of image recording and reproducing systems, images are recorded (reproduced) on photographic materials in accordance with image signals representing the images. The degree of surface gloss of the photographic material varies in accordance with the size of emulsion particles contained in the emulsion layer, the presence or absence of a protective layer, and the presence or absence of a matting agent in the protective layer. For example, if the emulsion particles contained in the emulsion layer are fine particles, the surface of the photographic material will be glossy. If the emulsion particles contained in the emulsion layer are coarse particles, the surface of the photographic material will be matte (non-glossy). Also, if a matting agent is contained in the protective layer, the surface of the photographic material will be non-glossy. If no matting agent is contained in the protective layer, the surface of the photographic material will be glossy. As a photographic material containing a matting agent, a novel silver halide photographic material has been proposed in Japanese Unexamined Patent Publication No. 2(1990)-191941. The proposed silver halide photographic material comprises a substrate and a non photosensitive layer, which is overlaid at least on one side of the substrate and which contains 5 to 70 mg/m.sup.2 of coarse particles having particle diameters falling within the range of 2 to 10 .mu.m and 70 to 190 mg/m.sup.2 of water-insoluble fine particles having particle diameters falling within the range of 0.3 to 1.3 .mu.m.
Whether the surface of the photographic material is or is not to be glossy depends on choice of a person who uses the photographic material. For example, some users will prefer a photographic material having a matte surface for the reason that, if the surface of the photographic material is glossy, an image recorded on the photographic material will be difficult to see due to light reflection from the surface. Other users will prefer a photographic material having a glossy surface for its high quality impression. In order for such requirements of users of photographic materials to be satisfied, it is necessary to prepare two kinds of photographic materials having identical photographic properties but having different degrees of gloss of surfaces, from the sides of which the recorded images are seen. Preparation of two such kinds of photographic materials has been a heavy burden to the manufacturers who supply photographic materials and to users who uses the photographic materials.